While Aimee sported a simple shirt and shorts combo, Steven went for an interesting look, which appeared to have been made from a number of bed sheets rather than actual clothes.
The rocker paired his hooded ensemble with a couple of beaded necklaces and let his long hair down.
Steven struck a few odd poses on the red carpet, before making his way into the bash with Aimee, who is rumoured to be more than just a friend.
According to reports, Aimee and Steven have been dating for a few months. A source told the Daily Mail: "It's early days between them, but they're certainly having fun together.
While at the party in Milan, Steven snapped a photo of himself and designer Stella, which he then sent to his daughter, actress Liv Tyler, on Twitter.
Steven is currently on a European tour with Aerosmith and last month he surprised two fans who were singing the band’s tune ‘Crazy’ in the Lithuanian capital Vilnius.
The band are set to perform at Calling Festival in London this weekend.